24 IOWA STUDIES IN NATURAL HISTORY 
margin; the smooth margin wider and more prominent than in the follow: 
ing form. Scutellum broad, regularly rounded, highly polished, the disk 
a little less densely and more obsoletely punctured than the sides, the 
punctuation in general not so deep as in Tf. nitiduloides. Coriaceous 
portion of hemelytra entirely black; corium usually without a distinct 
ridge between subcostal and cubital veins and even though the ridge may 
be slightly evident in some specimens it is never bounded inwardly by a 
deeply impressed line. Venter polished, sparsely punctate on disk, heay- 
ily and thickly punctate at sides; the forward extension of the last com- 
plete ventral segment in the male is more angular and acute than in T. 
nitiduloides. Ostiolar opening prolonged into a long, raised, shiny groove; 
the ostiolar area dull black and heavily Jongitudinally striate. Legs black; 
femora bearing a few short spines on under surface; tibiae furnished with 
long, black spines; tarsi reddish brown. Length, 5.0-6.0 mm. Width 
across pronotum, 3.5-4.5 mm. 
This is our largest and most striking species of Thyreocorid 
and in addition to its size it may be readily separated from our 
other forms by the highly polished surface on which the punctu- 
ation is not deep and by the broadly and regularly ovate form. 
Other and more detailed differential characters are mentioned 
in the preceding description. 
T. ater is distributed practically throughout the state and is 
usually present in some numbers in any locality, particularly in 
more or less moist and partly shaded situations. Specimens are 
at hand from Ames, Chariton, Decorah, Des Moines, Dubuque, 
Fort Madison, Grinnell, Hills, Iowa City, Independence, In- 
dianola, Lake Okoboji, New Hampton, Red Oak, Sae City and 
Storm Lake. 
At Ft. Madison in late June this form was found in abund- 
ance on the few stalks of barley left standing around the edges 
of a field that had just been cut. Nearby plants of the ribwort 
(Plantago aristata Michx.), were also heavily infested. At Lake 
Okoboji in mid-August one adult and several nymphs of various 
sizes were found among the seeds of the painted cup (Castilleja 
sessiliflora Pursh.). Usually the species could be taken in some 
numbers on the blue grass along the edges of both West Okoboji 
and Spirit lakes. 
Adults of this form hibernate successfully in our latitude for 
live individuals have been found as late as November 4 and in 
the spring as early as April 1 under rotting logs in pastures. 
While it has been found abundantly in a few places, great in- 
